For this review, we gathered data on published mutations in the Rho GTPases Rac1, Rac2, Rac3, Cdc42, RhoA, RhoB, RhoC, RhoH and RhoT1 using the cBio portal (http://www.cbioportal.org/), a database that collects cancer genomics data sets from tumor samples across cancer studies,89,90 and IntOGen (https://www.intogen.org/search), which assesses mutational data across multiple tumor types to identify potential driver mutations.91 The gene discussed is CDC42; the disease is cancer.